ଅର୍ଥ : Something that baffles understanding and cannot be explained.
ଉଦାହରଣ :
How it got out is a mystery.
It remains one of nature's secrets.
ସମକକ୍ଷ : closed book, mystery, secret
ଅର୍ଥ : A difficult problem.
ସମକକ୍ଷ : brain-teaser, conundrum, riddle